Ultrasound transmitting catheters have been utilized to successfully ablate various types of obstructions from blood vessels of humans and animals. Additionally, ultrasound transmitting catheters may be utilized to deliver ultrasonic energy to mammalian blood vessels for the purpose of preventing or reversing vasospasm, as described in U.S. Pat. No. 5,324,255 (Passafaro, et al.).
Particular success has been observed in ablation of atherosclerotic plaque or thromboembolic obstructions from peripheral blood vessels such as the femoral arteries. Successful applications of ultrasonic energy to smaller blood vessels, such as the coronary arteries, necessitates the use of ultrasound transmitting catheters which are sufficiently small and flexible to permit transluminal advancement of such catheter through the tortuous vasculature of the aortic arch and coronary tree. Accordingly, the safety and efficacy of removing obstructions from coronary arteries by way of ultrasound is largely dependent upon the size and flexibility of the ultrasound transmitting catheter(s) employed.
One particular type of ultrasound transmitting catheter which may be utilized to deliver therapeutic ultrasound to an intracorporeal treatment site comprises an elongate flexible catheter body having rigid distal tip or head member inserted into, and affixed thereto with at least one ultrasound transmission member extending longitudinally through the catheter body being coupled to the distal tip or head member, as described in U.S. Pat. No. 5,542,917 (Nita, et al.), and incorporated herein by reference.
Although these devices are of merit, there still exists a need in the art for further invention, development and refinement of ultrasound catheters to provide catheters with improved drilling performance.